Changing Vivax Malaria Transmission Features in the Republic of Korea during 2013-2014

Since the re-emergence of Plasmodium vivax in the Republic of Korea (ROK), 32,197 cases of vivax malaria have been reported (1993-2014). The aim of this study was to review the notification records of malaria to the Korean Centres for Disease Control and Prevention to investigate its transmission during the period 2013-2014. Reporting of malaria cases confirmed by microscopic examination is mandatory in the ROK. In this study, all available records of malaria cases and collected malaria vectors from eight locations in Gangwon Province, Gyeonggi Province, and Incheon Metropolitan City during 2013-2014 were reviewed. During the study period, 943 malaria cases were recorded. The number of cases reported in 2013 decreased by 30.6% (385 cases) compared with that in 2012 (555 cases); however, it increased by 44.9% in 2014 (558 cases) compared with that in 2013. This change may be due to the increased malaria vector density. Anopheles sinensis sensu lato increased at most collection sites in 2014 compared with that in 2013. In addition, the annual mean temperature and precipitation were slightly increased in 2014 compared with those in 2013. An increase in the number of malaria cases in a short period requires the attention of the officer in charge in order to treat the disease. More-intensive surveillance is needed in high-risk areas to identify the factors that affect the incidence of malaria in the ROK.